title: Predictors of poor neurological outcome in adult comatose survivors of cardiac arrest: a systematic review and meta-analysis. Part 1: patients not treated with therapeutic hypothermia.
abstract: OBJECTIVE
  To systematically review the accuracy of early (≤7 days) predictors of poor outcome defined as death or vegetative state (Cerebral Performance Categories [CPC] 4-5) or death, vegetative state or severe disability (CPC 3-5) in comatose survivors from cardiac arrest not treated using therapeutic hypothermia (TH). PubMed, Scopus and the Cochrane Database of Systematic reviews were searched for eligible studies. Sensitivity, specificity, false positive rates (FPR) for each predictor were calculated and results of predictors with similar time points and outcome definitions were pooled. Quality of evidence (QOE) was evaluated according to the GRADE guidelines.
  
  
  RESULTS
  50 studies (2828 patients) were included in final analysis. Presence of myoclonus at 24-48h, bilateral absence of short-latency somatosensory evoked potential (SSEP) N20 wave at 24-72h, absence of electroencephalographic activity >20-21μV ≤72h and absence of pupillary reflex at 72h predicted CPC 4-5 with 0% FPR and narrow (<10%) 95% confidence intervals. Absence of SSEP N20 wave at 24h predicted CPC 3-5 with 0% [0-8] FPR. Serum thresholds for 0% FPR of biomarkers neuron specific enolase (NSE) and S-100B were highly inconsistent among studies. Most of the studies had a low or very low QOE and did not report blinding of the treating team from the results of the investigated predictor.
  
  
  CONCLUSIONS
  In comatose resuscitated patients not treated with TH presence of myoclonus, absence of pupillary reflex, bilateral absence of N20 SSEP wave and low EEG voltage each predicted poor outcome early and accurately, but with a relevant risk of bias.
authors.affiliation: Department of Anaesthesiology and Intensive Care, Catholic University School of Medicine, Rome, Italy. Electronic address: sandroni@rm.unicatt.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Sandroni
authors.forename: Fabio
authors.initials: F
authors.lastname: Cavallaro
authors.forename: Clifton W
authors.initials: CW
authors.lastname: Callaway
authors.forename: Tommaso
authors.initials: T
authors.lastname: Sanna
authors.forename: Sonia
authors.initials: S
authors.lastname: D'Arrigo
authors.forename: Michael
authors.initials: M
authors.lastname: Kuiper
authors.forename: Giacomo
authors.initials: G
authors.lastname: Della Marca
authors.forename: Jerry P
authors.initials: JP
authors.lastname: Nolan
mesh_terms: D001927:Brain Diseases / Q000209:etiology*; D003128:Coma / Q000209:etiology*; D006323:Heart Arrest / Q000150:complications* / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced; D011379:Prognosis; D017741:Survivors; D016896:Treatment Outcome
keywords: Cardiac arrest; Post-anoxic coma; Prognostication